Lennox Heat Pump Troubleshooting

Lennox is a brand known for superior heat pump quality and energy efficiency. But even the most reliable heating units can experience problems. If you are having trouble with your heat pump and searching for a solution, look no further. We did some research, and here is what we found.

The most common problems with Lennox heat pumps are:

  1. Frozen components
  2. Low heating/cooling
  3. Water and refrigerant leaks
  4. Heating/cooling not working
  5. The unit won't turn ON

Some of these problems are minor, and you can resolve them without help. But more complex issues will require a heat pump specialist's expertise. Read on, as we will discuss further each problem and their respective solutions.

Residential heating and air conditioner compressor, Lennox Heat Pump Troubleshooting

Common Problems With a Lennox Heat Pump

A heat pump is an all-in-one system that functions as an air-conditioner during hot days and a heater during winter months. It is more energy-efficient than a furnace or boiler, and it's the best choice to use throughout winter.

Despite the higher cost, many prefer a heat pump over a furnace to warm their homes. It is a practical, long-term investment because it saves on energy and expenses because it uses electricity instead of gas.

HVAC heating and air conditioning residential units

With extended usage, however, the efficiency of heat pumps can decline due to technical and environmental factors. What is the first thing to do when faced with heat pump trouble? Below are the causes of the most common heat pump problems and what you can do to restore its efficiency.

1. Frozen Components

Central Air Conditioner frozen

A frozen heat pump can mean two things. One is a moisture buildup in the evaporator coils, and two, a layer of ice covers the outer unit. Heat pumps automatically go into defrost mode to prevent components from freezing up.

The heat pump draws warm air indoors and pumps it out during defrost mode, passing through the condenser coils to melt the ice. The defrost cycle will last about five to fifteen minutes at preset intervals.

You can read more about the defrost mode here: How Often Should A Heat Pump Defrost?

What to do

If there is a thick layer of ice covering the outdoor unit, it will prevent airflow, and the system can't defrost properly. Here's what to do:

For frozen outdoor units

  • Spray the ice with water using a hose to help melt it. Don't chip off the ice to avoid damaging the unit.
  • Can you pour hot water on a frozen heat pump? Yes, you can. If the ice is too thick, pour hot or warm water carefully and only enough to help melt the ice faster.

For frozen internal components

  • Remove the ice blocking the outer unit to improve airflow (see above instructions).
  • Clean dirty filters and evaporator coils to improve air circulation.

The newer models of Lennox heat pump cabinets are made of galvanized steel with a special PermaGuard coating for longer-lasting protection against corrosion. It is still prudent to remove ice as soon as it is visible to prolong its durability.

Other factors that can cause a heat pump to freeze up are defective outdoor fans, low refrigerants, and water leaks. If this is the case, it's best to call Lennox customer service to repair the unit.

2. Low Heating/Cooling

Residential house with a Hvac Unit installed

Proper air circulation is essential in a home because it regulates temperature and keeps the indoor air mold-free. The same is true with the heat pump's internal systems. It needs seamless airflow to run at an efficient level and avoid freezing, heating, and cooling problems.

If you notice a decline in the heat or cooling distribution indoors, it is a sign of insufficient airflow, likely caused by a dirty air filter.

What to do

Clean filters regularly and replace them as needed. You can purchase air filters from your nearest Lennox dealer. Another cause of insufficient airflow is an obstruction in the outdoor unit. Regularly clean out fallen leaves, grass clipping, shrubs, or outdoor debris that can collect around the unit.

3. Water and Refrigerant Leaks

air conditioner has been damaged so that the refrigerant leaks out of the system

Common signs of leaks include water stains on walls, mold growing on walls, and water pooling near the heat pump. A clogged drain line, a damaged drain pan, or a bad check valve is likely caused by water leaks. Additionally, stagnant water inside the unit can lead to component and electrical damage.

It's critical to identify whether excessive moisture is causing the leak or if it's a refrigerant leak. Identifying a refrigerant leak is difficult. But common signs include a greasy film on the water, a faint hissing sound, or a noticeable reduction in heating and cooling performance.

What to do

For refrigerant leaks

  • Turn off the heat pump at the main power source and inspect possible areas for a leak.
  • Call a technician to repair the leak or replace broken components and refill the refrigerant.

For water leaks

  • Locate the drain pan and remove any standing water using a dry cloth. Damage in the pan requires the expertise of a technician for replacement.
  • Locate the drain line and remove any debris potentially blocking the pipe.
  • For bad check valves, a technician should be able to identify if there is a leak in the pipes or valves.

4. Heating/Cooling Not Working

broken air conditioner calling help with a handyman for fixing

Previously we discussed the heat pump having reduced or low heating and cooling performance. But what if the heat pump is running but is not blowing out heat or cool air at all?

Possible reasons the heat pump cooling/heating is not working include:

  • Faulty thermostat
  • Incorrect thermostat setting
  • Low refrigerant
  • Outdoor unit is blocked
  • Defective reverse valve

What to do

  • Wrong thermostat setting - Check if the thermostat is at your desired setting, whether in cooling or heating mode.
  • Low refrigerant - Having too much or too little refrigerant can significantly reduce the heat pump's efficiency. Therefore, it's critical to have this checked by a technician, especially if you suspect a leak.
  • Faulty reverse valve - If the unit is cooling but not heating, and vice versa, you may have a stuck or damaged reverse valve. If it's stuck, a light tap on the body should do the trick, but it's time to call a technician if there's a mechanical problem.

5. The Unit Won't Turn ON

repairman fixes a heating system in a new home

It's frustrating if the heat pump won't turn on or doesn't seem to have power. Possible reasons for this include a faulty thermostat, loss of power source, or a faulty starter capacitor.

What to do

  • Faulty thermostat - Check that the thermostat is getting power by replacing the battery (if it runs on battery) or check the electrical panel if you have blown a fuse or a tripped circuit breaker.
  • Loss of power - Check if the indoor and outdoor units are ON. If units are on, check the electrical panels and the circuit breakers.
  • Faulty starter capacitor - One sign that you have a defective starter capacitor is if you hear a faint clicking sound when you turn on the unit, but it does not power on.

Pre-service Checklist

If none of the troubleshooting tips above work, it could be a sign of a more complex problem, and it's time to call Lennox customer service. Here's a checklist to save you from unnecessary service costs:

  • Ensure the electrical disconnect switches are turned on
  • Check that the room thermostat selector is in the right setting
  • See if the room thermostat system switch is in the correct setting
  • The access panels should be in place
  • The unit has clean filters

Try to check if the heat pump is still within warranty. Also, make sure you know the unit model number before calling customer service.

How To Contact Lennox Customer Service?

You can call your local Lennox dealer by visiting their official website and choosing 'homeowner solutions.' Go to the 'Find a dealer' section. Enter your zip code, and the page will redirect you to a list of dealers within your area.

In Closing

Residential heating and air conditioner compressor

Diagnosing heat pump problems is complicated. Also, be aware that this device holds onto electrical charges even if disconnected from a power source. It's best to avoid attempting to fix it if you don't have a working knowledge of basic electrical safety.

Contact a Lennox dealer directly instead of looking for an alternative technician to service your unit. If you haven't found the answer yet, check out these other articles:

Heat Pump Sounds Like Helicopter – What Could Be Wrong?

Heat Pump Leaking Water – What To Do?

How To Pump Down A Heat Pump [ A Step-By-Step Guide]

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One comment

  1. What is the problem with the Lennox heater pump when it doesn’t come out the heat mode. When you put it in the colding mode I replace the reverse valve.

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